Piezoelectric element, ink jet head, angular velocity sensor, manufacturing method thereof, and ink jet type recording apparatus

Abstract

In a piezoelectric element, an adhesive layer 12 is provided on a substrate 11, a first electrode layer 14 made of a noble metal containing titanium or titanium oxide is provided on the adhesive layer 12, and an orientation control layer 15 that is preferentially oriented along a (100) or (001) plane is provided on the first electrode layer 14. In the vicinity of a surface of the orientation control layer 15 that is closer to the first electrode layer 14, a (100)- or (001)-oriented region extends over titanium or titanium oxide located on one surface of the first electrode layer 14 that is closer to the orientation control layer 15, and the cross-sectional area of the region in the direction perpendicular to the thickness direction gradually increases in the direction away from the first electrode layer 14 toward the opposite side. Further, a piezoelectric layer 16 that is preferentially oriented along a (001) plane is provided on the orientation control layer 15.

Description

[0001] The present invention relates to a piezoelectric element having an electro-mechanical conversion function, an ink jet head using the piezoelectric element, an angular sensor, a method for manufacturing the same, and an ink jet recording apparatus including the ink jet head as printing means.[0002] Generally, a piezoelectric material is a material capable of converting a mechanical energy to an electrical energy and vice versa. A typical example of a piezoelectric material is lead zirconate titanate having a perovskite crystalline structure (Pb(Zr,Ti)O.sub.3) (hereinafter referred to as "PZT"). In PZT, the greatest piezoelectric displacement is obtained in the <001> direction (the c axis direction) in the case of a tetragonal system, and in the <111> direction in the case of a rhombohedral system. However, many of the piezoelectric materials are polycrystals made up of a collection of crystal grains, and the crystallographic axes of the crystal grains are oriented ...

AI Technical Summary

Benefits of technology

[0119] Thus, in the piezoelectric element of the present embodiment, the piezoelectric layer 16 having a desirable crystallinity and a desirable orientation can be obtained by depositing it by a sputtering method on the inexpensive silicon substrate 11, without using an expensive MgO single-crystal substrate. Therefore, it is possible to suppress the deviation in the piezoelectric characteristics of the piezoelectric element and to improve the reliability thereof while reducing the manufacturing cost. Moreover, a layer of a low crystallinity made of a Zr oxide is less likely to be formed, whereby it is possible to increase the breakdown voltage of the piezoelectric element.

Problems solved by technology

However, this method uses an MgO single crystal substrate as a base substrate, thereby increasing the cost of a piezoelectric element, and thus the cost of an ink jet head using the piezoelectric element.

Moreover, another drawback is that the variety of the substrate material is limited to the MgO single crystal.

However, while the methods described above are desirable methods that do not use an expensive MgO single-crystal substrate, it is difficult to obtain a well-oriented film having a desirable crystallinity in the film formation process, as in the case of forming a piezoelectric thin film on an MgO single-crystal substrate, because the piezoelectric thin film is formed by a sol-gel method.

Moreover, when piezoelectric elements are mass-produced with a sol-gel method, the amorphous piezoelectric precursor thin film is likely to be cracked due to changes in the volume during the degreasing step of removing organic substances.

Furthermore, in the step of heating and crystallizing the amorphous piezoelectric precursor thin film at a high temperature, the film is likely to be cracked or peeled off from the lower electrode due to crystal changes.

Therefore, as with a sol-gel method, the film is likely to be cracked or peeled off from the lower electrode due to crystal changes in the step of heating and crystallizing the film at a high temperature.

The crystallization of the PZT film proceeds gradually from the lower electrode side to the upper electrode side with a sol-gel method, whereas with a CVD method or a sputtering method, the crystallization of the PZT film proceeds randomly, resulting in irregular crystallization, and thus making the orientation control difficult.

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